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December 8th, 2018, 01:54 PM   #1
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Equilibrium Of Forces

Help me on this question; I don't get the answer and I keep obtaining 92cm. Maybe I don't draw the diagram well or something.

A uniform horizontal beam AB of mass 15kg and length 2m rest on a fulcrum at F distance x from A. Masses of 2kg, 3kg, 4kg and 5kg are hung at C, D, G and H, which are 24cm, 60cm, 120cm and 150cm from A respectively. Find the value of x.

Last edited by skipjack; December 9th, 2018 at 02:09 AM.
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December 8th, 2018, 02:06 PM   #2
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Show your calculation!
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December 9th, 2018, 01:00 AM   #3
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How will I show calculation without diagram?

Last edited by skipjack; December 9th, 2018 at 02:09 AM.
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December 9th, 2018, 02:10 AM   #4
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You should get x = 102cm regardless of your diagram. Check your arithmetic.
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December 9th, 2018, 06:26 AM   #5
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Yes sir,your answer is absolutely correct. Teach me how to solve sir
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December 9th, 2018, 07:42 AM   #6
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translational equilibrium in the vertical direction ...

$\Sigma F_y = 0 \implies F_f - (2g+3g+4g+5g+15g) = 0$, where $F_f$ is the upward force of the fulcrum on the beam.

rotational equilibrium about point A ...

$\Sigma \tau_A = 0 \implies F_f \cdot x - (2g \cdot 24 +3g \cdot 60 +4g \cdot 120 +5g \cdot 150 +15g \cdot 100) = 0$
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December 9th, 2018, 07:55 AM   #7
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I don't understand
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December 9th, 2018, 08:51 AM   #8
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Quote:
Originally Posted by Harmeed View Post
I don't understand
Then you are ill-prepared to complete such a problem. I recommend you research the conditions for static equilibrium. Here's a link where you can start ...

Static Equilibrium
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December 9th, 2018, 10:08 AM   #9
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Thank you very much sir. I'll really make use of this. Can I have a link of some of the important topics in physics like this? I really need it, sir.

Last edited by skipjack; December 9th, 2018 at 10:15 PM.
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December 12th, 2018, 01:01 AM   #10
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Problems about objects in contact with each other tend to be covered fairly well at an elementary level in school textbooks whose titles don't mention physics.

For the type of equilibrium problem posted here, I suggest reading this short article.
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